WEDNESDAY, Oct. 24 (HealthDay News) -- All pregnant women should be vaccinated against whooping cough, preferably in their last trimester, a panel of U.S. advisers recommended Wednesday.

Getting vaccinated during pregnancy means a mother can pass immunity to whooping cough to her baby, the U.S. government panel explained. Whooping cough, also known as pertussis, is a highly contagious bacterial disease that attacks the respiratory system.

The recommendation comes at a time when the United States is on track to record the highest number of whooping cough cases since 1959, according to the U.S. Centers for Disease Control and Prevention. So far, more than 32,000 cases have been reported and 16 people have died, most of them infants.

Of the infants who get pertussis, 30 percent to 40 percent get it from their mothers, and more than half need to be hospitalized. Of those hospitalized, one in five gets pneumonia and one in 100 dies, according to the CDC.

"This is a very good idea," said Dr. Marc Siegel, an associate professor of medicine at NYU Langone Medical Center in New York City, said of the recommendation. "This vaccine is safe during pregnancy," Siegel noted, with an annual flu shot being the only other vaccination approved for pregnant women.

The pertussis vaccine's protection only lasts 10 years, which may be one reason why there's an epidemic of this respiratory disease, Siegel said.

Since infants can only start getting the pertussis vaccine at 2 months of age, they must rely on the immunity passed to them by their mothers, he said.

"The best way to protect the infant is to protect the mother," Siegel said. "If you give vaccine to a pregnant woman you are going to get some degree of protection [for the infant]."

Siegel said that immunity is also passed to the infant through breast milk, a process called passive immunity.

The expert panel, known as Advisory Committee for Immunization Practices, specifically recommended that all pregnant women be given a so-called T-dap vaccination, which protects against tetanus, diphtheria and pertussis, for every pregnancy. The CDC typically follows the panel's recommendations.

If a woman wasn't vaccinated during pregnancy, she should get vaccinated immediately after giving birth, the panel added.

If the new recommendations were followed, there would be a 33 percent reduction in cases, a 38 percent reduction in hospitalizations and a 49 percent reduction in deaths, according to CDC spokeswoman Alison Patti.

In 2011, the panel recommended that only pregnant women who had not had a T-dap vaccination be vaccinated, but only 3 percent of pregnant women got the vaccination after that recommendation, Patti said.

Usually, when a woman becomes pregnant, her immunity against pertussis has worn off since she was probably vaccinated as a teen, which is why it's important to be re-vaccinated, he said.

Laufer also believes that any adult likely to be in contact with a newborn should be vaccinated. This includes fathers, grandparents and other family members, he said.

Pertussis is known for uncontrollable, violent coughing that often makes it hard to breathe. After coughing fits, sufferers often need to take deep breaths, which results in a "whooping" sound. Pertussis most often affects infants and young children and can be fatal, especially in infants under the age of 1, according to the CDC.